Operation Fireball (Span: Operación Bola de Fuego) was the initial Argentinean military land operation in March 1980 in which they launched an offensive and preventive invasion of Brazil, partially in response to the Aerolineas Argentinas 404 incident on February 27. Launched on March 24 with the codeword "Fireball" being broadcast to readied Argentinean forces, the initial strikes and movement of infantry and armored vehicles caught Brazil completely off guard and allowed Argentina to advance within sixty miles of Curitaba within 25 days. The remainder of the fighting throughout the late spring and summer was mainly contested on Brazilian soil, and in August and September Brazil launched a broad counteroffensive in taking advantage of Allied retreats in the north. This resulted in Operation Trench (Span: ), the defensive operations that Argentina would employ in Cisplatina and northern Argentina during late 1980 and most of 1981.
Fireball was successful in depleting Brazilian resources in the south initially, taking out critical military installations that had prior been unmolested by Allied assaults, and was both the catalyst and backbone of the broader 1980 Argentinean invasion of Brazil, which also included aerial and naval components and pulled Argentina officially into the NATO-led Allied Forces.